metal over shingles

I am getting a new metal roof. My two options are to remove the old, two layer shingle roof and install the metal or put the new metal on top of the existing two layers of shingles. Will leaving the two layers of old shingles in place and putting metal over them have a tendency to build up and retain more upstairs heat in the summer than removing the two layers of shingles and having a one layer roof of metal? My roof is exposed to sunlight most of the day here in Virginia.		Richard Howard 8/7/2013	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18635/find/
Richard, What type of metal roof are you having put on? In most applications, the additional thermal mass of the shingles will add to the retained heat in the roof assembly. Eric		Eric Novotny An informed customer is the Best Customer! 8/13/2013	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18636/find/
I thought part of the environmental enhancement of metal was to keep old shingles out of the landfills. What about one layer of shingles? How is metal helpful except for the person who owns my house 30 years from now not having to pollute that environment?		Guest User 6/26/2017	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18637/find/
I have a few different thoughts from those posted here a few years ago. Here's an article I have put together on this subject: https://www.asktoddmiller.com/articles/should-existing-asphalt-shingles-be-removed-before-a-metal-roof-is-installed/ And a short video: https://www.youtube.com/watch?v=bfD-0xvdJGc		Todd Miller Isaiah Industries, Inc. 6/26/2017	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/18638/find/

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